Safety syringe

ABSTRACT

A syringe apparatus and process is provided for retracting a needle from a hypodermic syringe following the completion of an injection. The hypodermic syringe has a plunger which, upon completion of the injection, is forced downwardly against a needle support deformable base, severing sacrificial supports. An end portion of the needle tears a base portion of the plunger and propels the needle into a hollow region of the plunger such that the needle is contained entirely within the plunger.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.09/139,008, filed Aug. 24, 1998, now U.S. Pat. No. 6,074,370, which is acontinuation of U.S. application Ser. No. 08/783,665, filed Jan. 15,1997 now U.S. Pat. No. 5,800,403, which is a continuation of U.S.application Ser. No. 08/481,093, filed Jun. 7, 1995 now U.S. Pat. No.5,613,952, which is a continuation-in-part application from U.S.application Ser. No. 08/359,001 filed on Dec. 16, 1994 now abandoned,which was a continuation of Ser. No. 07/813,115 which was filed on Dec.23, 1991, now U.S. Pat. No. 5,211,629.

BACKGROUND OF THE INVENTION

This invention relates generally to the art of syringes and moreparticularly to a syringe which reduces the likelihood of unintentionalpuncture or pricking of human skin. In recent history, the transmissionof contagious diseases, particularly those brought about exclusively bythe co-mingling of human body fluids, has been of great technologicalinterest. One of the particular problems has been associated with theuse and disposal of hypodermic syringes, particularly among healthcareprofessionals. There have been various devices developed for thedestruction of the needles or cannula used in such syringes. Additionaldevices have been developed for capping of syringes which attempt tominimize the likelihood of accidental puncture. The accidental punctureor pricking of a finger, or any other part of the body, after thetreatment of a patient with a contagious disease, particularly a deadlycontagious disease, results in a high likelihood of transmission of thatdisease. Various syringes have been developed in the prior art toattempt to minimize the likelihood of accidental puncture after patienttreatment.

One such device is described in U.S. Pat. No. 4,973,316 to Dysarzwherein a needle is retracted into the barrel of the syringe after theuse thereof. Another such device is described in U.S. Pat. No. 4,921,486to DeChellis, et al. One of the earlier patents in this regard was U.S.Pat. No. 2,460,039 issued to Scherer, et al.

Other references disclosing devices relating to needle retraction in asyringe include U.S. Pat. No. 4,994,034 to Botich et al, U.S. Pat. No.4,838,869 to Allard, and U.S. Pat. No. 5,114,410 to Batlle, GB 2 197 792to Powers et al., WIPO 90/06146 to Nacci et al., and WIPO 90/03196 toUtterberg et al. While all such devices seek the same goal of preventingaccidental puncture, considerable room for improvement exists.

SUMMARY OF THE INVENTION

It is thus an object of this invention to provide a novel hypodermicsyringe which minimizes the likelihood of accidental puncture.

It is a further object of this invention to provide such a syringewhich, after utilization, isolates the used needle so as to render suchneedle harmless, and automatically indicates that the syringe representsa biohazard.

It is a further and more particular object of this invention to providesuch a hypodermic syringe which is operable utilizing only one hand.

It is a further and yet more particular object of this invention toprovide such a syringe which automatically, upon the end of aninjection, retracts its needle to prevent its reuse, while sealing theneedle within the body of the syringe to prevent leakage of residualfluids.

It is a further object of the invention to provide a simple device,which is manufacturable in high volumes.

These as well as other objects are accomplished by a hypodermic syringehaving a barrel with a plunger movable therein to inject a fluid througha hollow needle thereof. A hollow needle is housed in a passagewaywithin a needle assembly. Positioned between the passageway within theneedle assembly and a shelf on an internal wall of the syringe barrel isa deformable base, with integral flexible supports. The deformable baseforms a liquid tight seal with the barrel, at the needle end of thebarrel. The deformable base houses an enlarged head of the needle whichenlarged head is in contact with energy storage means within thepassageway in the needle assembly. The plunger has a thin, rupturableweb on an end thereof which is part of a boot covering the end of theplunger, the boot, including the web, being liquid impermeable forforcing a liquid from the barrel upon movement of the plunger. Uponcompletion of an injection, the boot-covered plunger contacts thedeformable base, and upon application of force at the plunger, movessuch base downward. Continued application of force causes the flexiblesupports to flex and move over the needle assembly, permitting thedeformable base to move the enlarged head of the needle downward untilfurther movement of the enlarged head is blocked by the needle assembly.With the enlarged needle head blocked by the needle assembly, continuedforce at the plunger causes the deformable base to move around theenlarged needle head. As the deformable base moves around the needleassembly, the enlarged needle head begins to protrude from thedeformable base and come into contact with the web on the boot of theplunger. Continued force causes the enlarged needle head to tear the webof the boot, positioning the enlarged needle head just inside a hollowportion of the plunger. The torn portion of the web creates a flap justinside the hollow plunger. As the plunger moves the deformable basestill further, the enlarged needle head looses contact with thedeformable base, which triggers a release of energy from the energystorage means in the passageway, projecting the needle with its enlargedhead into the hollow portion of the plunger. Once inside the plunger,the needle is trapped by its enlarged head behind a flexible catchwithin the plunger. Final movement of the plunger causes the plunger tobecome substantially locked in the barrel and causes a liquid tight sealto be created between the plunger and the syringe body. A closing memberplaced on the front of the needle assembly completely seals the syringeto prevent residual fluids from escaping. Completion of the needleretraction also automatically highlights an indicia such as a biohazardlabel which alerts persons handling the device that the syringe has beenused and represents a potential biohazard.

In an alternative embodiment of the syringe according to this invention,a barrel, needle assembly, needle head, and deformable base of differentstructures than above are utilized wherein the deformable base ispositioned between sacrificial supports in the needle assembly and aninternal wedged end of the barrel. Upon completion of injection, theboot contacts the deformable base, and upon application of force at theplunger, moves the base downward, initially breaking the liquid tightseal between the base and the barrel. Continued application of forcecauses the sacrificial supports within the needle assembly to sever,permitting the deformable base to move the enlarged head of the needledownward until further movement of the enlarged head is blocked by thepassageway in the needle assembly. With the enlarged needle head blockedby the passageway, continued force at the plunger causes the deformablebase to move around the enlarged needle head. As the deformable basemoves forward, the enlarged needle head begins to protrude from thedeformable base and come into contact with a thin, rupturable web on theboot of the plunger. Continued force causes the enlarged needle head topenetrate the web of the boot, positioning the enlarged needle head justinside a hollow portion of the plunger. As the plunger moves thedeformable base still further, the enlarged needle head looses contactwith the deformable base, which triggers a release of energy from theenergy storage means in the passageway, projecting the needle into thehollow portion of the plunger. Once inside the plunger, the needle istrapped by its enlarged head within the plunger. Final movement of theplunger causes the plunger to become captured in the barrel at the backof the syringe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 of the drawings is a cross-sectional view of the syringe of thisinvention in its operational state.

FIG. 2 of the drawings is a cross-sectional view of the syringe of thisinvention in its post-operational state.

FIG. 3 is an isolated sectional view of the needle assembly of thisinvention.

FIG. 3A of the drawings is a cross-sectional view along line 3A—3A ofFIG. 3.

FIG. 4 of the drawings is an isolated sectional view of the deformablebase.

FIG. 4A is a cross-sectional view along line 4A—4A of FIG. 4 showing thecavity for the needle head and integral flexible supports.

FIG. 5 of the drawings is an elevational side view of the energy storagemeans.

FIG. 6 of the drawings is an elevational view of the plunger seal.

FIG. 7 of the drawings is an isolated view of the needle with itenlarged head.

FIG. 8 of the drawings is an elevational view of the needle guard,showing the needle assembly plug tethered to the tip of the needleguard.

FIG. 9 of the drawings is an isolated sectional view of the plunger bootof this invention.

FIG. 9A is a cross-sectional view along line 9A—9A of FIG. 9, showingthe plunger boot.

FIG. 9B is an enlarged sectional view of the encircled area of FIG. 9.

FIG. 10 of the drawings is an isolated sectional view of the barrel ofthis invention.

FIG. 10A is a cross-sectional view along line 10A—10A of FIG. 10.

FIG. 11 of the drawings is an isolated sectional view of a plunger inaccordance with this invention.

FIG. 11A is an enlarged sectional view of the encircled area of FIG. 11.

FIG. 11B is a cross-sectional view along line 11B—11B of FIG. 11illustrating needle capturing means.

FIGS. 12, 13, and 14 of the drawings are cross-sectional subassemblyviews illustrating assembly of the needle, enlarged head, base, barrel,needle assembly, and energy storage means.

FIG. 15 of the drawings is a cross-sectional view of the plunger of thisinvention, showing assembly of the plunger boot and the plunger seal onthe plunger.

FIG. 15A of the drawings is a partial sectional view of the plungershowing an alternative embodiment for the plunger seal.

FIG. 16 of the drawings is a cross-sectional view of the completedassembly of the syringe.

FIG. 17 of the drawings is a graph depicting the force/balancerelationship upon which the syringe operation is based.

FIGS. 18, 19, 20, 21, 22, 23, 24, 25, 26, and 26A of the drawings arecross-sectional views of the apparatus of this invention showing thesequence of operation, after the injection cycle.

FIG. 27 of the drawings is an elevational view of the syringe prior toneedle retraction.

FIG. 28 of the drawing is an elevational view of the syringe subsequentto needle retraction wherein an indicia has been revealed.

FIG. 29 of the drawings is a cross-sectional view of an alternativeembodiment of the syringe of this invention in its operational state.

FIG. 30 of the drawings is a cross-sectional view of the alternativeembodiment of the syringe of this invention in its post-operationalstate.

FIG. 31 of the drawings is an isolated view of an alternative embodimentof the needle assembly of this invention.

FIG. 32 of the drawings is a cross-sectional view drawn along line 32—32of FIG. 31.

FIG. 33 of the drawings is a side view of an alternative embodiment ofthe deformable base of this invention.

FIG. 34 of the drawings is a cross-sectional view drawn along line 34—34of FIG. 33.

FIG. 35 of the drawings is a side view of the needle with an enlargedhead of an alternative embodiment according to this invention.

FIGS. 36, 37, 38, 39, 40, 41, 42 and 43 of the drawings are sectionalviews of an alternative embodiment of the syringe of this inventionillustrating the sequence of operation after the injection cycle.

FIGS. 44, 45, 46 and 47 of the drawings are sectional views ofembodiments of a syringe where no supports are utilized.

FIG. 48 of the drawings is a sectional view of a preferred embodiment ofa syringe where no supports are utilized.

DETAILED DESCRIPTION

In accordance with this invention it has been found that a syringe maybe provided for normal operation but, which upon completion of normaloperation and continued movement of the plunger, results in atriggering, of the needle or cannula to project such needle harmlesslyinto the plunger and body of the syringe. Once trapped inside theplunger and body of the syringe, the needle is no longer subject toaccidental pricking or poking of human tissue thus minimizing thelikelihood of transfer of contagious disease which may be carried byfluids contained on the surface of or within such needle. To preventpossible leakage of residual fluids in the needle, the syringe can besealed after use, and after such use an automatic indication is giventhat the syringe represents a biohazard. Various other advantages andfeatures will become apparent from a reading of the followingdescription given with reference to the various figures of drawing.

FIGS. 1 and 2 of the drawings illustrate the syringe 1 of this inventionwith the needle 3 illustrated in FIG. 1 in its normal pre-injectionposition. FIG. 2 of the drawings, however, shows the final positionafter operation of this invention wherein the needle 3 has been trappedand rendered harmless after the injection has taken place, and theplunger 7 has been locked within the barrel 5 of the syringe. Thesyringe 1 in accordance with this invention has relatively fewcomponents, which along with their function, will now be described withreference to the drawings in sequence beginning with FIG. 1.

The syringe 1 has a barrel 5 and a plunger 7 mounted therein. The needle3 is contained within a needle assembly 9, which is fixed to barrel 5 byultrasonic welding means or other permanent attaching means.

Needle 3 has an enlarged head 13, generally cylindrical in shape,positioned within and engaged by deformable base 11. Enlarged head 13has a top 14, which is preferably flat and diametrically cylindrical.The top of enlarged head 13 can be concave in one embodiment. Below top14 on enlarged head 13 are a plurality of diametrically wider areas orgradually extending bands, illustrated as areas 15 and 17, which areslightly wider than top 14. The bottom portion of enlarged head 13 iscylindrically smooth and defines a contacting portion 25 for contactingthe energy storage means. By appropriately positioning the enlargedneedle head 13 within deformable base 11 for a substantially matingengagement, the geometries of top 14 and area 15 of enlarged head 13 canbe substantially mated and locked within deformable base 11 so that aliquid tight seal between needle head 13 and deformable base 11 iscreated at top 14 of enlarged head 13. As seen in FIG. 1, all ofenlarged head 13 but a portion of the bottom portion is contained withinthe deformable base.

Needle assembly 9 has contained therein energy storage means,illustrated as spring 21, within a passageway 23, which is in contactwith contacting portion 25. Deformable base 11 is positioned betweenbarrel base shelf 2 and one end of needle assembly 9 wherein supports 31of base 11 contact the end of the needle assembly.

Plunger 7 has a hollow 41 therein and has a boot 43 covering an endthereof which is fluid impermeable for forced movement of a fluid inbarrel 5 during ordinary injection. A portion of boot 43 is illustratedas having been torn by the needle head in FIG. 2, with boot web 79laying over in the front of plunger 7.

Preferably, plunger 7 has an enlarged thumb push 45 which, uponcompletion of a compression stroke, is substantially locked within amating head portion 47 of barrel 5. As seen in FIG. 2 fitting plunger 7within barrel 5 also produces a sealing action between plunger seal 4and guard ring, 16, preventing release of residual fluids at the back ofthe syringe, left in the needle after use. Plunger 7 has needlecapturing means 49 therein which is illustrated in FIG. 2 as preventingthe release of needle 3 from plunger 7. Also illustrated in FIG. 2 isclosing member 51, illustrated as a plug, inserted into the front ofneedle assembly 9 to prevent residual fluids which may drain from needle3, after the capture thereof, from leaking from the front of thesyringe. It is envisioned according to this invention that variousstructures of closing members can be utilized, such as the plug as shownand also a capping member, as long as the opening left by needleretraction can be closed.

Reference will now be made to FIGS. 3 through 11B to more particularlyillustrate the components of this invention as described above.

FIG. 3 is an isolated sectional view of needle assembly 9 of thisinvention. Passageway 23 is shown and is defined within needle assembly9.

FIG. 3A of the drawings is a cross-sectional view along line 3A—3A ofFIG. 3 illustrating the needle assembly 9 of this invention.

FIG. 4 is an isolated sectional view illustrating deformable base 11which defines a passage therethrough for passage of the needle head, asdiscussed in more detail later. Deformable base 11 is designed tosubstantially matingly engage enlarged head 13. As seen in FIG. 4 basewedge 6 is provided, below where top 14 of enlarged head 13 can fit, forproper positioning of the needle in the deformable base. Further,cylindrical barrel seals 8 are provided to create proper sealing actionbetween base 11 and barrel 5. The diameter and width of the barrel seals8 can be made to create an optimum seal, while minimizing static anddynamic friction between base 11 and barrel 5. Also illustrated in FIG.4 are supports 31, preferably formed as opposing, semicircularcantilevered beams projecting from the upper body 12 of base 11. Eachsupport 31 has an inward engaging flange 32 for engaging a lower portionof enlarged head 13 and an end of the needle assembly, as shown in FIG.1. Needle head seal 10 is further illustrated in FIG. 4 and is where top14 of enlarged head 13 can fit. The diameter and width of needle headseal 10 is designed to provide optimum sealing with top 14, whileminimizing static and dynamic friction between enlarged head 13 and base11.

FIG. 4A of the drawings is a cross-sectional view along line 4A—4A ofFIG. 4 illustrating deformable base 11. A preferred material for base 11is an elastomer. Supports 31 are illustrated in the preferred embodimentas a pair of opposing, semicircular cantilevered beams, however, it isenvisioned according to this invention that supports 31, could beconnected and unitary or divided up further.

FIG. 5 of the drawings is an elevational side view of the energy storagemeans illustrated as spring 21.

FIG. 6 of the drawings is an elevational view of plunger seal 4illustrated in one embodiment as an O-ring seal.

FIG. 7 of the drawings is an isolated view of needle 3, or cannula, withenlarged head 13. Top 14, wider areas 15 and 17, and contactor 25 on thebottom portion are illustrated. Also illustrated in phantom is thehollow portion 16 of the needle.

FIG. 8 shows a side view of a needle guard 12, with closing member 51attached at the end thereof. Closing member 51 is attached or tetheredby a breakable tab 52 which can be of plastic construction and which isbroken to remove closing member 51. As illustrated, closing member 51 ispreferably a plug which is attached by tab 52 to the needle guard at anangle wherein tab 52 connects to closing member 51 away from the end ofclosing member 51 which can be inserted or plugged into the needleassembly after needle retraction. As discussed above, the closing memberof this invention can be of various types, such as a cap or a plug asshown, as long as the opening left by needle retraction can be closed.Preferably, the opening is closed off so that a liquid tight seal isobtained. The angular attachment of the closing member preferred hereinand illustrated in FIG. 8 allows a person completing needle retractionto handle just the needle guard to insert the closing member into theneedle assembly where the needle was positioned prior to retraction.Quite advantageously, this can be accomplished with the user's handsalways positioned behind the opening in the needle assembly left as aresult of needle retraction.

FIG. 9 is an isolated sectional view of boot 43 of this invention. FIG.9A of the drawings is a cross-sectional view along line 9A—9A of FIG. 9illustrating boot 43. FIG. 9B is an enlarged sectional view of theencircled area of FIG. 9. Referring to FIGS. 9, 9A and 9B, a thin,rupturable web 79 is shown as a portion of boot 43. To aid in therupturing process of the web, tear groove 26 and tear groove 28, shownin FIG. 9B, are provided. The thickness of web 79 and the tear groovesare selected to withstand normal operating pressures within syringe 1,as shown in FIG. 1, but to allow relative ease in the puncturing of web79 by enlarged needle head 13, shown in FIG. 6. The preferred materialfor boot 43 is an elastomer.

FIG. 10 is an isolated sectional view of barrel 5. FIG. 10A of thedrawings is a cross-sectional view along line. 10A—10A of FIG. 10showing finger support flange 81 of barrel 5 of this invention.Referring to FIGS. 10. and 10A, at the finger support flange 81 ofbarrel 5 is shown an undercut 47 for locking the plunger into thebarrel. At the opposite end of barrel 5, base shelf 2 and nose shelf 14are illustrated. These internal offsets receive the base and the needleassembly respectively.

FIG. 11 of the drawings is an isolated sectional view of plunger 7 inaccordance with this invention. Capturing means 49 is illustrated.Plunger boot termination 16 is also illustrated and is designed toreceive rupturable boot 43.

FIG. 11A is an enlarged sectional view of the encircled area of FIG. 11and illustrates cavity 30 for receiving plunger seal 4 and inclinedsurface 18 for fitting and substantially locking the plunger into thebody of the syringe.

FIG. 11B is a cross-sectional view along line 11B—11B of FIG. 11 furtherillustrating needle capturing means 49.

Given the components described above, assembly in several primary stepsis required to produce the syringe. FIGS. 12 through 16 illustrate thesesteps so as to result in a finished product. Needle 3 is first insertedinto enlarged head 13. With reference to FIG. 12, the first assemblystep is accomplished by inserting needle 3 into deformable base 11between flexible supports 31 for a substantially mating engagement. Basewedge 6 is positioned between top 14 and wide area 15 of enlarged head13 which blocks needle 3 movement in both directions. A liquid tightseal between enlarged head 13 and needle head seal 10 on base 11 asshown in FIG. 12 is created around the edge of top 14 of enlarged head13. With needle 3 blocked into base 11, the next assembly step isaccomplished.

In the next step of the assembly process, the subassembly in FIG. 12 isinserted into the front end of barrel 5 as shown in FIG. 13, until base11 contacts and is positioned against base shelf 2. When base 11 iscompletely inserted as shown in FIG. 13, base 11 is compressedcircumferentially in the direction of needle head 13, and a liquid tightseal is produced between base 11 and barrel 5.

To complete assembly of needle assembly 9 with barrel 5, as shown inFIG. 14, the energy storage means is first placed into passageway 23.The preferred embodiment of energy storage means is spring 21. Needleassembly 9 is then fixed to barrel 5 by threading needle 3 through thecenter of spring 21 in passageway 23 and inserting needle assembly 9into the front of barrel 5, until needle assembly 9 contacts and ispositioned against nose shelf 14. Permanently joining needle assembly 9and barrel 5 can be accomplished by ultrasonic welding around thecircumference of barrel 5 at overlap 81, or any other permanentattaching means can be utilized. Attachment of needle assembly 9 tobarrel 5 creates a liquid tight seal between the two parts. As a resultof this assembly step, the end of needle assembly 9 is positioned justin contact with engaging flanges 32 of supports 31, thus preventingmovement of base 11 and needle 3 contained therein for normal syringeuse.

In the final step of assembly, plunger seal 4 and boot 43 are placedonto plunger 7 as shown in FIG. 15. Boot 43 is preferably placed ontoplunger 7 so that web 79 is just at the end of the plunger. Plunger 7 isthen inserted into barrel 5. FIG. 15A is a partial sectional view of theend of the plunger with a plunger seal showing an alternative embodimentwherein the plunger seal is formed as an integral and unitary part ofthe plunger so that the seal as provided by use of an O-ring isaccomplished by forming the ring as an integral part of the plunger. Tocomplete the assembly as shown in FIG. 16, needle guard 12 is placed onneedle assembly 9, with closing member 51 tethered at the tip of needleguard 12. It will be apparent to those in the art that there existsother possible sequences of assembly other than those described hereinthat can be used to produce the completed assembly as shown in FIG. 16,producing the same syringe ready for operation.

The syringe operates on a “force/balance” principal as depicted in thegraph of FIG. 17. In the graph normal operation is represented byregions I and II. In these regions limited positive and negative forcesare applied between the plunger 7 and body 5, shown in FIG. 18, fornormal operating functions of filling the syringe and for injections.Positive forces are defined as forces which move the plunger into thesyringe body, while negative forces are defined as those forces whichpull the plunger from the syringe body. Typical “filling” and“injection” cycles are depicted in regions I and II, respectively. Aslong as the positive force applied between the plunger 7 and body 5 ofsyringe 1 is below threshold 34, base 11 balances the operating forceand remains in its assembled position, as shown in FIG. 18. But, forpositive forces applied to the syringe above threshold 34, base 11becomes unbalanced and begins to move in the direction of needleassembly 9. Once force above threshold 34 is applied and maintained,operation of the syringe moves into region III, where the needle isretracted into the plunger of the syringe. In region III, points 83, 85and 87 represent a typical device where base 11 first begins to move,needle head 13 is released and plunger 7 becomes substantially lockedinto body 5 respectively.

The sequence of operation will now be described with regard to FIG. 1and FIGS. 18 through 28. As can be seen, FIG. 1 is a cross-sectionalview of safety syringe 1. For normal syringe operating forces, safetysyringe 1 operates as any conventional syringe. For use, the syringe isfilled from an ampule in a normal manner, as standard proceduredictates. Once filled, the injection cycle is accomplished, againaccording to standard practice. At completion of the injection cycle,plunger boot 43 is just mating with base 11, as shown in FIG. 18, andall fluids, which can be, are expended from syringe 1 through theneedle. Before the syringe is released or discarded, by the user, theneedle retraction cycle should be accomplished.

At the beginning of the needle retraction cycle, syringe 1 is usuallyheld between the index finger and the middle finger at support flange81, with the thumb resting on thumb push 45, presumably the same as thesyringe was held at completion of the injection cycle. Plunger 7 iscontacting base 11 at boot 43, as shown in FIG. 18.

With reference to FIG. 19, force is applied between finger supportflange 81 and thumb push 45. This force is transmitted along plunger 7to deformable base 11 and supports 31. As the force increasessufficiently supports 31 begin to flex open away from one another asshown in FIG. 19, wherein engaging flanges 32 move away from and losecontact with the enlarged needle head 13 and flex open just enough topass over passageway 23 and to allow further movement of base 11 andneedle 3 toward an end of the barrel.

As shown in FIG. 20, the continued application of force applied toplunger 7 continues to cause supports 31 to ride up on and around theneedle assembly as deformable base 11 moves further. As the deformablebase and the enlarged needle head are forced toward the end of thebarrel, the bottom portion of enlarged head 13, which extends partiallyinto the needle assembly prior to the retraction process, is forcedfurther into the needle assembly, until wide area 17 contacts the end ofthe needle assembly and prevents any further movement of the enlargedhead into the needle assembly by its greater diameter than passageway 23within the needle assembly. This allows the plunger to force the base todeform and pass around the now stationary enlarged needle head. Spring21 is fully compressed in the process by contactor 25 of the needlehead.

With reference now to FIG. 21, as deformable base 11 moves furthertoward the end of the barrel, needle head 13 begins to protrude frombase 11 and come into contact with web 79 of boot 43 on plunger 7.Continued force causes further translation of base 11 and needle head 13to tear web 79 of boot 43, positioning enlarged needle head 13 justinside hollow 41 of plunger 7 while wide area 17 remains embedded withindeformed base 11, as shown in FIG. 21.

With reference to FIG. 22, continued translation of deformable base 11causes wide area 17 to eventually lose contact with deformable base 11,creating a trigger-like release of enlarged head 13. Upon thistrigger-type action, energy stored within spring 21 is released andimparted to needle 3 to project needle 3 into hollow 41 of plunger 7, asillustrated in FIG. 23.

Referring now to FIG. 24, it is seen that needle 3, at its enlarged head13, contacts capturing means 49 which is a flexible catch thatelastically flexes to permit enlarged needle head 13 to pass through theconstriction formed by capturing means 49 and an inner wall of plunger7. This is further illustrated in FIG. 25 where needle head 13 is shownhaving passed capturing means 49 and being captured within hollow 41 ofplunger 7 wherein the needle head will move back past the capturingmeans. At this point, it should be noted that plunger 7 has beenmatingly and substantially locked within barrel 5 by mating head portion47 engaging a portion of the plunger near thumb push 45. As shown inFIG. 26A, a liquid tight seal between plunger seal 4 and guard ring 16is created.

To finish the operational sequence, closing member 51 tethered to theend of needle guard 12, can be inserted into opening 22 of needleassembly 9 as shown in FIG. 26 and described with reference to FIG. 8.Closing member 51 can be forced into position by pressing it against aheavy, solid object. Once closing member 51 is lodged into position,closing member 51 can be separated from needle guard 12 with a twistingaction, leaving syringe 1 as shown in FIG. 26. This closure process cantherefore be advantageously accomplished with a user's hands alwaysremaining behind the opening left by the retracted needle.

As a result of accomplishing the needle retraction cycle as described,syringe 1 is left as shown in FIG. 26. Also preferably accomplishedduring the needle retraction cycle is revelation and amplification of anindicia or label such as biohazard label 24, as shown in FIG. 28. Beforethe needle retraction cycle, base 11 is under biohazard label 24 as seenin FIG. 27 wherein the label is not readable. It is preferred thatbiohazard label 24 be printed in black, or any other appropriate color,and that base 11 also be the same or substantially similar color so thatbiohazard label 24 is unnoticeable to the user. It is also preferredthat boot 43 be of a different, contrasting color. After the needleretraction cycle, base 11 is no longer left under the biohazard label,and boot 43 is under the label, as shown is FIG. 28. Since boot 43 isany appropriate highly contrasting color relative to base 11 and thebiohazard label, such as orange when the other two are black, biohazardlabel 24 is significantly revealed and amplified and becomes verynoticeable to the user or other people, as shown in FIG. 28.

FIGS. 29 and 30 of the drawings illustrate the syringe 101 of thisinvention with the needle 103 illustrated in FIG. 29 in its normalpre-injection position. FIG. 30 of the drawings, however, shows the netresult of this invention wherein needle 103 has been trapped andrendered harmless after the injection has taken place, and the plungerhas been locked within the barrel of the syringe. Syringe 101 inaccordance with this invention is similar to syringe 1 described aboveand has relatively few components. Components of syringe 101 that aredifferent from syringe 1 above are the deformable base, the enlargedneedle head, and the needle assembly and the barrel.

Syringe 101 has a barrel 105 and a plunger 107 mounted therein. Needle103 is contained within a needle assembly 109, which is fixed to barrel105 by ultrasonic welding means or other permanent attaching means.

Needle 103 has an enlarged head 113 mounted within deformable base 111.Enlarged head 113 has a wedge portion 115 and a circular flange portion117. By appropriately positioning the enlarged head 113 withindeformable base 111, the geometries of the flange portion and wedgeportion of enlarged head 113 substantially lock such enlarged headportion within the deformable base, while also creating a liquid tightseal between needle head 113 and deformable base 111.

Needle assembly 109 has contained therein energy storage means,illustrated as spring 121 within a passageway 123. Enlarged needle head113 has a contacting portion 125 which contacts energy storage means121. Sacrificial supports 131 position deformable base 111 within needleassembly 109.

Plunger 107 has a hollow 141 therein and is terminated by a boot 143having a rupturable web 179, the boot being fluid impermeable formovement of a fluid in the barrel during ordinary injection. Web 179 ofboot 143 is illustrated as having been ruptured in FIG. 30.

Preferably, plunger 107 has an enlarged compression section at thumbpush 145 which, upon completion of a compression stroke, is lockedwithin a mating head portion 147 of barrel 105. Plunger 107 has needlecapturing means 149 therein which is illustrated in FIG. 30 aspreventing the release of needle 103 from plunger 107. Also illustratedin FIGS. 29 and 30 is an absorption means 151, such as cotton, tocollect any fluids which may drain from needle 103 after the capturethereof.

FIG. 31 of the drawings is an isolated view of needle assembly 109 ofthis invention. Sacrificial supports 131 and passageway 123 areillustrated in partial phantom.

FIG. 32 is a cross-sectional view along the line 32—32 of FIG. 31,further illustrating sacrificial supports 131 and passageway 123 withinneedle assembly 109.

FIG. 33 of the drawings is a side view of deformable base 111. Apreferred material for base 111 is an elastomer. As seen in FIG. 33,counterbore 173 and thrubore 175 are provided for proper positioning ofthe needle in the deformable base.

FIG. 34 is a cross-sectional view along the line 34—34 of FIG. 33further illustrating deformable base 111.

FIG. 35 of the drawings is a side view of needle 103 or cannula.Contactor 125, circular flange 117 and enlarged head 113 with wedgeportion 115 are illustrated. Also illustrated in phantom is the hollowportion 116 of the needle.

The sequence of operation of syringe 101 will now be described withregard to FIG. 29 and FIGS. 36 through 43. As can be seen, FIG. 29 is across-sectional view of safety syringe 101. For normal syringe operatingforces safety syringe 101 operates as any conventional syringe. For use,the syringe is filled from an ampule in a normal manner, as standardprocedure dictates. Once filled, the injection cycle is accomplished,again according to standard practice. At completion of the injectioncycle, plunger 107 is just mating with base 111, as shown in FIG. 36,and all fluids, which can be, are expended from syringe 101. Before thesyringe is released, or discarded, by the user, the needle retractioncycle should be accomplished.

At the beginning of the needle retraction cycle, syringe 101 is usuallyheld between the index finger and the middle finger at support flange181, with the thumb resting on thumb push 145, presumably the same asthe syringe was held at completion of the injection cycle. Plunger 107is just mated with base 111 at boot 143, as shown in FIG. 36.

With reference to FIG. 37, force is applied between finger supportflange 181 and thumb push 145. This force is transmitted along theplunger to deformable base 111 and sacrificial supports 131. As theforce increases sufficiently, the liquid tight seal between barrel 105and deformable base 111 is broken, and sacrificial supports 131 begin tofracture.

As shown in FIG. 38 further force is applied at plunger 107. Sacrificialsupports 131 are severed and deformable base 111 moves forward, furthercompressing energy storage means 121. Deformable base 111 moves forwarduntil circular flange 117, on needle head 113 which is in translationwith base 111, comes into contact with the end of needle passageway 123.

With reference now to FIG. 39 enlarged needle head 113 is blocked bypassageway 123, and continued force at plunger 107 causes deformablebase 111 to deform and move around circular flange 117 on enlargedneedle head 113 as deformable base 111 moves forward, enlarged needlehead 113 begins to protrude from base 111 and come into contact withrupturable web 179 of boot 143, positioning enlarged needle head 113just inside hollow 141 of plunger 107 while circular flange 117 remainsembedded within deformed base 111, as shown in FIG. 39.

With reference to FIG. 40, continued translation of deformable base 111causes circular flange 117 to eventually lose contact with deformablebase 111, creating a trigger-like release of circular flange 117. Uponthis trigger-type action, energy stored within spring 121 is releasedand imparted to needle 103 to project needle 103 into hollow 141 ofplunger 107, as illustrated in FIG. 41.

Referring now to FIG. 42, it is seen that needle 103, at its enlargedhead 113, contacts capturing means 149 which deforms to permit enlargedhead 113 to pass through the constriction formed by capturing means 149.This is further illustrated in FIG. 43 where needle 103 is showncaptured within hollow 141 of plunger 107. At this point, it should benoted that plunger thumb push 145 has been locked within the matingsection 147 of barrel 105. As syringe 101 is tilted downward, fluidsremaining in needle 103 flow within hollow 141, down the exterior sideof passageway 123 to absorbent means 151 where the fluids are absorbedand prevented from being released from the interior of syringe 101.

FIGS. 44 and 45 of the drawings illustrate syringe 1 of this inventionwherein the flexible supports are not utilized. It has been foundaccording to this invention that syringe 1 can function to retract theneedle without supports 31 when small syringes, such as 1 cc syringesare used.

FIGS. 46 and 47 of the drawings illustrate syringe 101 of this inventionwherein sacrificial supports 131 are not utilized. It has been foundaccording to this invention that syringe 101 can function to retract theneedle without sacrificial supports 131 when small syringes, such as 1cc syringes, are used.

FIG. 48 of the drawings illustrates a preferred embodiment of a syringe161 according to the present invention where no flexible or sacrificialsupports are utilized. This embodiment is particularly suitable forsmall syringes, such as 1 cc, and includes a cylindrical deformable base163 having a central passage therethrough which matingly engages acylindrical enlarged needle head 165 which is attached to an end ofhollow needle 167. A needle assembly 169 is attached to an end of barrel171 opposite an end for insertion of plunger 173. Needle 167 passesthrough a passageway defined through needle assembly 169, and an energystorage means such as spring 173 is positioned within the passageway.Enlarged needle head 165 includes two cylindrical sections of differentdiameters with the larger section being held entirely within base 163prior to initiation of needle retraction and the lower cylindricalsection extending partially into the needle assembly and having acontacting portion 175 on an end thereof for contacting spring 173. Base163 is biased in position by spring 173 against shelf 177 and byfriction from barrel 171 prior to initiation of needle retraction.

Needle ejection through web 179 of boot 181 occurs as discussed withreference to syringe 1 above, which is incorporated herein, with base163 being forced downwardly around the needle assembly except nosupports are utilized. As base 163 moves downwardly, the enlarged needlehead tears web 179, and when enlarged needle head 165 loses contact withbase 163, needle 167 is ejected into plunger 7.

It is thus seen that this invention provides a novel syringe apparatuswhich minimizes the likelihood of accidental puncture, is operable by asingle hand and which upon completion of injection captures the utilizedneedle and renders such harmless within the plunger and body of thesyringe. As various other advantages and features will become apparentto those of skill in the art from a reading of the foregoing descriptionwhich is exemplary in nature, such modifications and variations areembodied within the scope of this invention as defined by the followingappended claims.

What is claimed is:
 1. A process for retracting a needle at thecompletion of subcutaneous injection with a hypodermic syringe,comprising the steps of: forcing a plunger of said syringe downwardly toforce a needle support deformable base downwardly and break sacrificialsupports; forcing an end portion of said needle to tear a base portionof the plunger; and propelling said needle into a hollow of said plungersuch that said needle is contained entirely within said plunger.
 2. Theprocess according to claim 1 wherein said step of forcing an end portionof said needle to tear a base portion of the plunger further includesrupturing a web covering a terminus of the plunger.
 3. A process forretracting a needle at the completion of subcutaneous injection with ahypodermic syringe, comprising the steps of: forcing a plunger of saidsyringe downwardly to a first location to force a needle supportdeformable base downwardly and break sacrificial supports; forcing saidplunger downwardly to a second location, thereby directing an endportion of said needle to rupture a web defined by a terminus of theplunger; and propelling said needle into a hollow of said plunger suchthat said needle is contained entirely within said plunger.